Improvement in artificial arms



UNITEE STATES PATENT OEErcE.

IGNATIUS STOFFEL, OF WASHINGTON, DISTRICT OF COLUMBIA.

IMPROVEMENT IN ARTIFICIAL ARMS.

Specification forming part of Letters Patent No. 57.594. dated August'28, 1866.

To all 'whom it may concern:

Be it known that I, IGNATIUS STOEFEL, of Washington, District ofColumbia, have iuvented a new and Improved Artificial Fore- Arm; and Ido hereby declare the following is a full and exact description thereof,reference being had to the accompanying drawings, and to the letters ofreference marked thereon.

Figure l is a perspective View, showing the fore-arm and hand extended.Fig. 2 shows the hand closed; Figs. 3 and 4, views, in differentpositions, of the levers and forked connecting-rods which operate themechanism giving motion to the hand; Figs. 5 and 6, different views ofthe mechanism by which the forked connecting-rod may be detached fromthat which operates the hand, allowing the latter to be kept open orclosed independent of the motion of the former; Fig. 7, an upper sideview of the hand, showing the construction of the joints of the fingers,&c.

Similar letters of reference in each of the several ii gures indicatecorresponding parts.

This invention relates to certain improvements in the construction ofartificial forearms to be attached and used when a stump is left belowthe elbow of the natural arm, by which motion may be transmitted todifferent parts of the artiticial arm by different movements of thestump, and are mainly improvements on that described in patent to me,dated January 10, 1865, for artificial arm; and it consists, first, inthe manner of attaching and op erating the springs which represent thetendons in the natural hand to the last phalange, at or near the joint,dispensing with the guiderin gs which represent the tendinous bands inthe natural hand, and thus avoid friction; second, in the constructionand operation of the thumb, making the articulation and pivoting thelever at the second instead of the third joint, thereby increasing thestrength of the thumb and the power exerted by it; third, in theconstruction, arrangement, and operation of the trigger; fourth, in themovable band or support t'or the stump of the fore-arm, fifth, in thebent or bell-crank lever at or near the elbow-joint, by which greaterplay can be given to said joint; sixth, in the guide-rings at or nearthe elbow-joint and the outside of the upper fastening or case on thearm near the shoulder, through which rings passes the cord which is usedin operating the arm.

To enable others nskilled in the art to make and use my invention, Iwill proceed to describe its construction and operation.

In Figures 1, 2, 5, 6, and 7, the letter A desi gnates a case or shell,representing the forearmin Fig. 1, the hand extended; in Fig. 2, thesaine closed. Fastened to the last phalanges a a a a near the joint bysmall hinges, or their equivalents, a-re the springs or bands b b b b,which correspond to the tendons in the natural hand, their inner endsbeing fastened to a stir.- rup, c, Fig. 2, the movements of whichoperate all the fingers, and by means of a loop, n., attached to theouter end of said stirrup, and receiving the thumb-lever e, with fulcrumat f, motion is also transmitted to the thumb g and with much greatereffect than if the fulcrum should be placed at the third ljoint, as inthel patent referred to.

To the stirrup cis attach ed a con nectin g-rod, h, Figs. l, 5, and 6,formed of two dat bars, side by side, fastened together at the outer endand passing through the post or guide in, Figs. 5 and 6. One of thesebars has its upper edge serrated, forming a ratchet. The other bar isplain; -but both have near their outer ends a deep notch or recess intheir upper sides, at i, in which rests the forked connecting-rod k,which receives motion through the bent lever or bell-crank from themotion of the stump 0f the fore-arm, and transmits it to the mechanismalready described.

Pivoted to the post or support m, Figs. 5 and 6, and parallel to and oneach side ofthe connecting-rod h, are levers :t fr, the elevation ordepression of which throws the forked connecting-rod out or in the notchThese levers are operated by the trigger it, Figs. l, 2, 5, and 6, thehook y of which presses upon the short arms thereof and throws upwardthe long ones, disconnecting the rods h and k. At the same time a spuron the trigger sinks into the ratchet-bar of rod h and holds the lingersin any position in which they may happen to be at the time, as shownpartially in Fig. 5. In Fig. 6 the trigger is shown withdrawn and thetwo connecting-rods in gear.

Figs. 3 and 4 show the bent or bell-crank lever l in differentpositions, and also the bands o and p, the latter being rigid orpern1anently fastened to the straps or bars u; the former pivoted to thesaine at q, and adjustable to or from the elbow-joint to suit thedifferent lengths of stumps of arms to which they are to be attached.The length of lever-arm lis also adjustabletorthesamepurpose. Attachedto the band p is a loop or ring, s, which, in combination with the' oneat t, Fig. l, is used for the passage of a cord to assist in operatingthe arm.

lhe construction of the articulations or joints (except the last ones)of the tingers and hand do not .difter substantially from those shown inthe patent referred to, and the inanner of securing the artificial tothe remaining part of the natural arm is so apparent thata descriptionis not considered necessary.

Having thus described my invention, what I claim as new, and desire tosecure by Letters -Patent, is-

1. The construction of the last or outerarticulations or joints, ormeans of operating the outer or last phalanges by the steel bandsWithout the guide, substantially as show n and described.

2. Pivoting the thumb and lever connecting therewith at the secondjoint, in the manner and for the purpose substantially as described.

3. The construction, arrangement, and operation of trigger n, incombination with levers x x and connectingrods h and 7c, substantiallyas described.

4. The adjustable band o, when constructed and arranged as described.

5. The bent or bell-crank lever l, constructed and arranged to operateas and for the purpose described.

6. The loops or rings s and t, when arranged as and for the purposedescribed.

